The present invention relates to an amplifier using a plurality of transistors and, more particularly, to a transistor amplifier for operating amplifying elements in parallel with each other.
FIG. 2 shows an example of a conventional technique of an amplifier using a transistor. Referring to FIG. 2, an emitter-grounded transistor 1 is used as an amplifying element, an impedance element 2 is connected between the base and collector of the transistor 1, and an impedance element 3 is connected between its emitter and the ground, thereby obtaining a required gain. In operation characteristic curves of this amplifier shown in FIG. 3, a point of intersection between an I/O linear curve Q and a cubic strain curve P, i.e., an intercept point R is determined by the characteristics of the transistor 1.
In order to obtain a higher intercept point in the above conventional technique, however, although a specific transistor must be selected as the transistor 1 or an optimal operation point must be selected, this cannot be easily realized.